From af950964f0ecad72df8f893e27ab33413275ec49 Mon Sep 17 00:00:00 2001
From: Marian Piatkowski <marian.piatkowski@iwr.uni-heidelberg.de>
Date: Sat, 7 Jun 2014 16:37:38 +0200
Subject: [PATCH] [Bugfix] Exploit analytical properties in MINRES to avoid
special-casing for complex case
---
dune/istl/solvers.hh | 18 ++++++------------
1 file changed, 6 insertions(+), 12 deletions(-)
diff --git a/dune/istl/solvers.hh b/dune/istl/solvers.hh
index 8926ae294..5927702c4 100644
--- a/dune/istl/solvers.hh
+++ b/dune/istl/solvers.hh
@@ -1033,16 +1033,6 @@ namespace Dune {
private:
- template<typename T>
- typename enable_if<is_same<field_type,real_type>::value,T>::type conjugate(const T& t) {
- return t;
- }
-
- template<typename T>
- typename enable_if<!is_same<field_type,real_type>::value,T>::type conjugate(const T& t) {
- return conj(t);
- }
-
void generateGivensRotation(field_type &dx, field_type &dy, real_type &cs, field_type &sn)
{
real_type norm_dx = std::abs(dx);
@@ -1059,12 +1049,16 @@ namespace Dune {
sn = cs;
cs *= temp;
sn *= dx/norm_dx;
- sn *= conjugate(dy)/norm_dy;
+ // dy is real in exact arithmetic
+ // so we don't need to conjugate here
+ sn *= dy/norm_dy;
} else {
real_type temp = norm_dy/norm_dx;
cs = 1.0/std::sqrt(1.0 + temp*temp);
sn = cs;
- sn *= conjugate(dy/dx);
+ sn *= dy/dx;
+ // dy and dx is real in exact arithmetic
+ // so we don't have to conjugate both of them
}
}
--
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